Food Webs

1. Food Webs

2. Review

3. Food chains represent flows of matter and energy • They are always pyramid shaped

4. Energy Flow in Ecosystems • Three things can happen to the energy taken in by the organisms in a trophic level: • It can be passed on to the next trophic level in the food chain when the organism is eaten. • It can become stored in detritus. This energy is passed on to decomposers when the detritus decays. • It can be converted to heat energy by inefficient chemical reactions, radiated by warm bodies, or in friction due to movement. The heat energy is lost to the surroundings, and cannot be regained by living organisms.

5. Grazer Food Chains . • Begins with plants

6. Grazer Food Chains

7. Detritus Food Chain . • Begins with dead material or waste

8. numbers are very high organisms are small don’t move a lot consume organic wastes releasing a great deal of energy mostly as heat converting it back into its inorganic nutrient form algae, bacteria, slime molds, fungi, protozoa, insects, mites, crustaceans, centipedes, mollusks Detritus Food Web

9. Detritus Food Web • By far the most important food web in a forest. • Not much is removed from the forest, nutrients are recycled.

10. Detritus Food Web • Detritus food chains are connected to a grazing food chain when consumers of a grazing food chain feed on the decomposers of the detrital food chain • In some ecosystems, less than 1% of energy may move through the grazing food web while over 99% moves through the detritus food web

11. Food Webs

12. Pond Food Web

13. Land Food Web

14. Marine Food Web

16. Pond Food Web